2003 Audi A4 1.8t with 87 octane

[04r1]

I have been arguing forever with my girlfriend about putting premium fuel in her 2003 Audi A4 1.8t and she rarely does it. I keep telling her she is going to screw the motor up and she does not beleive me. She really doesnt drive it hard but I still think she is in for it if she doesnt start using good fuel. Please give your thoughts so I can show her and not have to resort to punching her in the face Thanks

[Skinner]

whats the manual say??

[04r1]

It says premium but she thinks it doesnt matter to put 87 in it.

[Rotarded1647545491]

The car will run fine on 87 octane once the ECU adjusts for the O2 readings. About the only thing that will happen is the car will not run at "peak" performance, but will not harm any components. I've been running my 1.8T on 87 for 4k miles without a problem.

 

ECS tuning has chips for the 1.8T to maximize performance on 87/89, 91, and 93 octane.

[04r1]

The car will run fine on 87 octane once the ECU adjusts for the O2 readings. About the only thing that will happen is the car will not run at "peak" performance, but will not harm any components. I've been running my 1.8T on 87 for 4k miles without a problem.

 

ECS tuning has chips for the 1.8T to maximize performance on 87/89, 91, and 93 octane.

 

 

Yeah, it definately runs like shit and has NO power on 87 octane.

[Buckeye1647545503]

man brian don't you understand she is saving like a dollar with each fill up and all she has to deal with is her car running like a car that cost 1000's of dollars less. I mean why drive a audi when you can make it run like Kia

[Bam]

Yeah, it definately runs like shit and has NO power whilst STOCK.

 

*FIXED

 

Tell her she needs an APR Stage 3+ to fix her car, then tell her you'll drive her car all the time and she can put 87 in your truck.

 

That might scare her into putting premium into it. What's so hard to understand that the car needs the good stuff? It's only 20cents more/gal.

[04r1]

man brian don't you understand she is saving like a dollar with each fill up and all she has to deal with is her car running like a car that cost 1000's of dollars less. I mean why drive a audi when you can make it run like Kia

 

She is rich, money is not the issue. She just thinks its a waste.

[04r1]

*FIXED

 

Tell her she needs an APR Stage 3+ to fix her car, then tell her you'll drive her car all the time and she can put 87 in your truck.

 

That might scare her into putting premium into it. What's so hard to understand that the car needs the good stuff? It's only 20cents more/gal.

 

 

Why would she need an APR Stage 3+ when she doesnt use the power the stock motor has which isnt much. She doesnt drive the car for speed, she drives it cause its a nice car.

[Bam]

Why would she need an APR Stage 3+ when she doesnt use the power the stock motor has which isnt much. She doesnt drive the car for speed, she drives it cause its a nice car.

 

 

You missed the most important part of my post....YOU DRIVE IT!!! Who wouldn't want to get to drive a stg3+ vehicle everyday for free?

[Acec]

At least run 89/91 in it .... Just make sure oil changes aren't skipped ( see oil sludge probs all the time on the 1.8t's )

[04r1]

You missed the most important part of my post....YOU DRIVE IT!!! Who wouldn't want to get to drive a stg3+ vehicle everyday for free?

 

 

I could think of better ways to spend $5300 then having a 340hp Audi that would still be slow

[SPLN SUX]

Well the Volvo recommends 91 or higher but can run on as low as 87 (do they even sell 85 anymore???). Now that its colder, i can get away with 89 if i want, but i continue to dump 94 in it.

[TurboTank]

most people have no idea what your talking about....some people must think that they wont get any gas unless they pull up to the pump and push the big 8..7..if your dont know..you dont know. kinda the same thing as driving all over the city looking for cheaper gas....am i the only one that thinks that is retarded???look at all the gas you waisting looking for cheap gas. unlike the norm..i goto one gas station and buy one gas..no giving a shit about the price.

 

my 2cents

[AudiOn19s]

I think that Audi calls for 91. My car would spark knock on warm days with 89 even when it was stock. Now that I've got software It never sees anything but 93.

 

I guess that now that it's cold it's less of an issue but she should still be using as least 89.

[GRN96WS6]

Fuck it let her find out the hard way if she doesn't want to listen to you about it.

 

 

Not your car not your problem, when she calls to bitch just say I told you so but you didn't want to listen.

 

*shrug*

[SPLN SUX]

most people have no idea what your talking about....some people must think that they wont get any gas unless they pull up to the pump and push the big 8..7..if your dont know..you dont know. kinda the same thing as driving all over the city looking for cheaper gas....am i the only one that thinks that is retarded???look at all the gas you waisting looking for cheap gas. unlike the norm..i goto one gas station and buy one gas..no giving a shit about the price.

 

my 2cents

 

Yup... Sunoco 94

[villision1647545496]

Yeah, it definately runs like shit and has NO power on 87 octane.

 

 

IN theory the car should make more power on 87. Like if you have a race-gas tune on a street car/racecar, then only use 87, you will make more power. However with that igntion that advaced from the tune, good bye motor. So yeah, you have more power but it only last about 1 run if you are lucky enough to get that in. Moral of the story, fuel does matter, but not on your level, stock everything. Audi engineers, have the stock ecu tuned for it.

 

You are fine.

 

Ty

[Orion]

pull one of the sparg plug wires. when it runs terribly, tell her it probably has something to do with the gas. take her to go fill it up with the good stuff, and then put the wire back on, when it runs great, look at her with a straight face and say "i told you so."

[04r1]

pull one of the sparg plug wires. when it runs terribly, tell her it probably has something to do with the gas. take her to go fill it up with the good stuff, and then put the wire back on, when it runs great, look at her with a straight face and say "i told you so."

 

Hah, best idea yet

[Nitrousbird]

A lot of cars that require premium fuel, along with getting poor performance on 87 (because the ECU is pulling timing to compesate), they will also get worse fuel mileage, which will kill off any money savings by filling up with 87.

 

With a car like that, in the winter, 89 is probably alright, then premium in the summer. 87 just isn't a good idea though.

[Renner]

IN theory the car should make more power on 87. Like if you have a race-gas tune on a street car/racecar, then only use 87, you will make more power. However with that igntion that advaced from the tune, good bye motor. So yeah, you have more power but it only last about 1 run if you are lucky enough to get that in. Moral of the story, fuel does matter, but not on your level, stock everything. Audi engineers, have the stock ecu tuned for it.

 

You are fine.

 

Ty

 

 

This is assuming that the car does not have a knock sensor feedback loop, which is incorrect. The combustion chamber design, cam timing, and ecu tune are all designed to run ideally on 91 octane for the stock 1.8T as well as the 2.8 V6. On 87 octane, the car does knock, and the ecu does pull timing, which of course decreases power.

 

In the end, the non-ideal timing levels (and decreased torque production) can end up giving you worse fuel economy, because your brake specific fuel consumption (BSFC) just went up. The car now requires a larger volume of air (and of course fuel) to accelerate at the same rate as with the 91 octane timing curve.

 

Also, during light load cruising the ecu reads the O2 sensor in closed loop, and trims fuel to reach the 14.67:1 stoichiometric afr target as needed. As mentioned above, at these levels less timing=less torque production, which means the throttlebody must be opened further to maintain say 65 mph because of the once again higher BSFC with 87 octane. A larger volume of air requires a larger volume of fuel to maintain stoich, therefore the mileage is slightly decreased for this reason as well.

 

So in this case, although not exactly ideal, the 87 octane will not damage her engine if she is just driving it normal like most people out there, because the ecu will pull timing to eliminate knock damage. However, she could be losing some gas mileage for the reasons listed above regarding BSFC depending on how she drives. Anything above 91 octane would definitely be a waste for normal driving though.

 

Edit: Joe beat me to it.

[Trouble Maker]

Also, during light load cruising the ecu reads the O2 sensor in closed loop, and trims fuel to reach the 14.67:1 stoichiometric afr target as needed.

 

I thought under part throttle you could be lean (from stoich) and it's ok because you are not under full load? This would also cause a more complete burn of the fuel, i.e. better fuel economy. So most cars shot for above (numerically) stoich under part throttle?? Please correct me if I'm wrong, I do understand that you are just speaking in generalities too.

[villision1647545496]

This is assuming that the car does not have a knock sensor feedback loop, which is incorrect. The combustion chamber design, cam timing, and ecu tune are all designed to run ideally on 91 octane for the stock 1.8T as well as the 2.8 V6. On 87 octane, the car does knock, and the ecu does pull timing, which of course decreases power.

 

In the end, the non-ideal timing levels (and decreased torque production) can end up giving you worse fuel economy, because your brake specific fuel consumption (BSFC) just went up. The car now requires a larger volume of air (and of course fuel) to accelerate at the same rate as with the 91 octane timing curve.

 

Also, during light load cruising the ecu reads the O2 sensor in closed loop, and trims fuel to reach the 14.67:1 stoichiometric afr target as needed. As mentioned above, at these levels less timing=less torque production, which means the throttlebody must be opened further to maintain say 65 mph because of the once again higher BSFC with 87 octane. A larger volume of air requires a larger volume of fuel to maintain stoich, therefore the mileage is slightly decreased for this reason as well.

 

So in this case, although not exactly ideal, the 87 octane will not damage her engine if she is just driving it normal like most people out there, because the ecu will pull timing to eliminate knock damage. However, she could be losing some gas mileage for the reasons listed above regarding BSFC depending on how she drives. Anything above 91 octane would definitely be a waste for normal driving though.

 

Edit: Joe beat me to it.

 

OK I wrong. However, on an aftermarket ecu(aem, apex'i) would I be correct?

 

Ty

[SPLN SUX]

I thought under part throttle you could be lean (from stoich) and it's ok because you are not under full load? This would also cause a more complete burn of the fuel, i.e. better fuel economy. So most cars shot for above (numerically) stoich under part throttle?? Please correct me if I'm wrong, I do understand that you are just speaking in generalities too.

 

Correct. Under vacuum cars will run about 16-17:1.